This study examines whether individuals who engage in illicit, non-medical use of OxyContin are distinguishable from other non-medical users of opioids and whether OxyContin serves as a "gateway" to heroin and/or injection drug use. The study sample included active nonmedical users of opioids, who are 16 years or older and residents of Cumberland County, Maine. Possible associations between type of opioid used and behavioral and descriptive variables were assessed. The study sample was predominantly urban-dwelling, male, Caucasian, and economically disadvantaged. OxyContin users could only be distinguished from heroin users (cf non-heroin opioid users). Polyopioid use within the first year of initiation was associated with quicker progression to heroin and injection drug use.